Optical signals for communication may be generated by a single-mode source or a multimode source. Optical signals based on single-mode sources are carried by corresponding single-mode communication links, and optical signals based on multimode sources are carried by multimode communication links. The two types of communication links (single-mode, multimode) are incompatible with each other, resulting in a need to replace an entire communication link and related components of a computing system if upgrading from one type of optical signal to another.